Bolster snubbing mechanism for railway car truck



J. A. SHAFER June 7, 1966 BOLSTER SNUBBING MECHANISM FOR RAILWAY CAR TRUCK 2 Sheets-Sheet 1 Filed Feb. 2'7, 1965 INVENTOR.

BY $144.55 A. 5mm? Aime/vi) June 7, 1966 J. A. SHAFER 3,254,612

BOLSTER SNUBBING MECHANISM FOR RAILWAY CAR TRUCK Filed Feb. 27, 1965 2 Sheets-Sheet 2 INVEN TOR.

BY JZME; '4. 52/4/21? United States Patent 3,254,612 BOLSTER SNUBBING MECHANISM FOR RAILWAY CAR TRUCK James A. Shafer, East Cleveland, Ohio, assignor, by mesne assignments, to Midland-Ross Corporation, Cleveland, Ohio, a corporation of Ohio Filed Feb. 27, 1963, Ser. No. 261,404 16 Claims. (Cl. 105-197) This invention relates to railway car trucks which include a friction system for dampening the vertical oscillation of a car truck bolster relative to the side frame associated therewith. The invention is concerned primarily with an arrangement :for facilitating the removal of friction wedges, wedge springs, and any other elements of the friction system.

The prior art, including application Serial No. 188,599, filed March 29, 1962, by the present applicant, discloses various bolster snubbing mechanisms which may be considered, in the light of the present invention, primarily with respect to their convenience of assembly and disassembly, and the effect that the arrangement of such mechanisms has in facilitating the assembly and disassembly of a car truck as a Whole. Prior to this invention, the most convenient arrangement known is that which provides a chock. normally positioned between a side frame support and a friction wedge but which may be instantly displaced from its operating position. Subsequently, the other elements of the friction mechanism such as the wedge, the wedge spring and any other elements freed by removal of the chock, as well as the chock itself, may be withdrawn from the truck through the side frame window.

A principal object of the present invention is to further improve bolster snubbing mechanisms of the type which employ an initially removable chock to support a wedge in contact with a bolster to obtain still further advantages in car truck assembly and disassembly operations.

An important object is to provide a bolster snubbing mechanism including a chock in which extremely small displacement of the wedge from its Working position is required in order to free the chock for removal from the truck.

It is a further object to provide a car truck utilizing the above-mentioned chock which, when the next above object is achieved, may utilize a shorter wedge spring than heretofore required in a chock-type mechanism.

Still another object is to obtain more compact arrangement of the bolster snubbing mechanism than heretofore attained with the use of the initially removable chock whereby the column portion of a side frame may retain more extensive cross webbing and other transverse support.

Briefly stated, the invention resides in a car truck wherein the bolster is snubbed relative to one or both side frames thereof by a mechanism including a chock disposed between a support in the side frame and the friction wedge, the wedge positioned also against the bolster, and a spring disposed between the wedge and a seat therefor in the side frame. The side frame has a lateral opening enabling instantaneous removal therethrough of the chock when disengaged from the wedge.

' In slightly more expanded description, the car truck comprises a bolster; a side frame having: transversely spaced side walls, a bolster-opening flanked by two columns for receiving the bolster with its length in transverse relation to that of the side frame, a passageway contiguous with the bolster-opening and extending away therefrom between the walls, preferably to a window spaced longitudinally of the side frame from the bolster opening, and a support fixed between the walls within or "ice adjacent the passageway and defining a seat for the chock which is spaced from the bolster opening and faces theresurfaces against the nearest side wall of the bolster; a.

chock positioned within the passageway with its opposite ends facing transversely of the side frame; and a spring or other resilient means standing within the side frame against the wedge to urge the latter into wcdging relation with the bolster side and the chock. The chock is supported with its end surfaces facing transversely of the side frame. One of the side frame walls has an opening in approximate registry with the end of the chock adjacent thereto when the chock is positioned against its seat on the support. The wall opening is of a size and shape permitting passage of the chock into and out of the side frame. The side frame has another opening in its side wall opening into a region immediately adjacent the smaller end of the wedge formed by'its diverging side whereby the wedge may be loosened from its normal position to allow the chock to be traversed through th opening referred to above.

In the drawing with respect to which the invention is described:

FIG. 1 is a fragmentary side elevation of a car truck incorporating one embodiment of the invention.

FIG. 2 is a fragmentary view in section taken along line IIII of FIG. 1 illustrating a chock in normal working position.

FIG. 3 is a fragmentary side elevation of the car truck of FIG. 1 illustrating the friction wedge retracted from its working position by a pry bar, and a chock positioned for passing outwardly through a lateral open ing of the side frame.

FIG. 3a is an enlarged fragmentary elevation showing FIG. 4 is a perspective view of the chock employedin the embodiment of FIGS. 1 to 6.

FIG. 5 is an elevation in section of the side frame taken along line V-V of FIG. 1 with only the side frame shown in full line. Shown in dot-dash line but not shown in FIG. 1, is a portion of a pry bar and the friction wedge and the spring therefor in a depressed position.

FIG. 6 is fragmentary transverse horizontal section taken along line VIVI of FIG. 1.

FIG. 7 is a fragmentary side elevation of a car truck comprising a modified side frame and chock.

FIG. 8 is a perspective view of the chock included in the car truck of FIG. 7. V

Describing now the first embodiment as illustrated in FIGS. 1 to 6, and referring at the moment to FIG. 1, a car truck according to this invention comprises a bolster 5 and a side frame 6 having a bolster opening 7 through which the bolster extends with its length in transverse relation with the length of the side frame. As shown, the bolster is vertically supported from a spring seat 10 by a plurality of springs 11. An upstanding lateral lip 12 of the spring seat defines the lower extremity of. the bolster opening. The bolster (see FIG. 6) is locked from movement in its longitudinal direction relative to the side frame by a friction wedge 15 which extends into a lateral recess 16 in the side wall 11 of the bolster as defined by the surface of a Wear plate 18 lining the recess.

The wedge 15 extends in. the hflri zgntal, longitudinal direction of the side frame into an opening or passageway 20 contiguous with the bolster opening. The opening 20 extends internally and longitudinally of the frame Patented June 7, 1966 to a window 21 in the side frame in longitudinally spaced relation with the bolster opening. The opening 20 is intended to include generally that open region bounded by side walls 23 and 24 of the side frame, along the bottom by a web 25, and in its upper portion by a chock support 32. The web 25 has an upper surface and an integral boss 26 which define a spring seat 26a for a spring 27.

The opening 20 comprises generally the region within which the various elements of the bolster snubbing mechanism, including a chock 28, are received. Stanchions 22a and 22b of the column 22 are continuations of the walls 23 and 24 and partly define the opening 20 The stanchions are spaced at close clearance with side walls of the wedge 15. This clearance, along with close clear ance of the wedge with end surfaces of the bolster recess as shown in FIG. 6, limit the relative movement of the bolster transversely of the wedge to that needed for normal warping freedom within the car truck and for cushioning shocks resulting from movements of the bolster transversely relative to the side frames.

The opening 20 has an important function as a passageway to the window 21 for removal of the wedge spring 27 and the wedge 15 in the event either one of these parts must be replaced. It is thus essential that transverse portions of the side frame, such as the upper extremity of the web 25 at 31, and the lower extremity of a chock support 32 at 33 must be spaced sufficiently for passage of the wedge and the spring to the window 21.

The chock support 32 is located adjacent the opening 20 and serves as a partial boundary thereof. The support has a chock seat comprising areas 35 and 36 which meet at 37 in a dihedral angle extending transversely of the side frame 6. The chock 28 has a rear side comprising areas 38 and 39 which also meet in a dihedral angle of approximately the same magnitude as that of the chock seat. The chock seat and the rear side of the chock are thus arranged in a reentrant and projecting relationship along a vertical longitudinal plane of the side frame parallel to the walls 23 and 24 which prevents any shifting of the chock, when engaged by the Wedge, in any direction along this plane.

A principal feature of this invention is that the chock 28 may be removed from the side frame in the transverse direction thereof through an opening 40 provided essentially for this purpose in the side wall 24. The opening, 40 conforms as a minimum generally to the maximum cross section of the chock in a vertical longitudinal plane of the side frame and is of necessity at least slightly larger than this cross section in order to permit facile passage of the chock to and from its position on the chock seat 35, 36.

When the chock is provided with a longitudinal lug 44 on a lateral surface 45 extending between the rear side area 39 and the front side 46 of the chock, the opening 40 includes a notch 48 for passage of the lug 44 therethrough as shown in FIG. 3.

When the chock is in position against the chock seat 35, 36, as shown in FIG. 1 the lug 44 is positioned out of registry with the notch 48 since it is short enough to be partly positioned behind, i.e., in longitudinally overlapping relation with the wall 24. However, the opening 40 is long enough in the front to rearward direction of the chock to enable the chock to be separated from the chock seat 35, 36 for registry of the lug 44 with the notch 48 as shown in FIG. 3. Such separation is obtained as shown in FIGS. 3 and by use of a pry bar 51. FIG. 3 shows the chock 28 separated from its seat, 35, 36 in registry with the opening 40 and the notch 48 thereof for passage out of the side frame. The wedge 15 is shown depressed with respect to its regular operating position shown in FIG.'1 so that the chock may be separated from the. seat sufiiciently in the longitudinal direction of the side frame to be shifted through the opening 40.

Comparing FIGS. 1 and 3, the friction wedge 15 is shown depressed in FIG. 3 from its normal working position of FIG. 1 in the wedge-receiving region located between the chock 28 and the bolster 5. For purposes of illustration, the position of the wedge is shown lower than that necessary to disengage the chock 28 from the chock seat 35, 36.

Other structural features of the chock 28 include a pair of lugs 53, 54 of which each protrudes from an end surface of the chock. As shown in FIG. 2, the lug 53 spaces the body of the chock from the wall 23 to maintain the corners of the chock away from any fillets which join the check seat 35, 36 to the side wall 23. Although but one of the lugs 53, 54 are used at any one time, both lugs are provided in order that the chock may be used in the corresponding chock-receiving region on the opposite side of the bolster opening within a side frame having duplicate snubbing mechanisms on opposite sides of the bolster. This avoids the necessity for constructing thechocks as rights and lefts.

A further feature of the chock is that it is hollow and its hollow region 56 opens into each end surface by apertures 57 and 58. The apertures are of smaller diameter than the main portion of the region 56 to provide a finger grip needed in removing the chock from the side frame. The hollow region 56 also lightens the chock and makes the casting of such chocks less subject to defects.

As hereinbefore suggested, a necessary condition to removing the chock is to retract the wedge 15 from working position. It is desirable to obtain such retraction by manual use of the pry bar 51. Hence, the wedge 15 is constructed with a web 61 having an upper surface which provides a surface or seat 62 for receiving the end surface of a pry bar, and an undersurface 63 functioning as a spring seat in opposed relation with the side frame spring seat 26a on the web 25. An opening for the pry bar 51 through the side wall 24 is provided by a boss 65 defining a pry bar receiving aperture 66 in its outer lateral extremity. The boss 65 is constructed integrally with a flange 68 having a width as shown in FIG. 5. As shown, the boss 65 terminates outwardly from the side frame in the same vertical longitudinal plane of the side frame as the flange 68. This places a fulcrum surface 69 for the pry bar outwardly from the general plane of the side wall 24 at a distance from the point of application of the bar to the wedge 15,

such as to achieve favorable leverage ratios for displacing the wedge.

The side frame is further provided with apertures 70, 71 in the side walls 23 and 24, respectively, which extend on a transverse horizontal axis in fixed relation with the side frame which intersects the wedge spring 27 at its normal working position. The purpose of the apertures 70, 71 is to receive a pin of sufficient length to extend through the side frame to hold the spring in a free length condition and the wedge 15 supported thereon backwardly out of the bolster opening on such occasions as withdrawal or insertion of the bolster relative to the side frame. When this is to be accomplished, it is necessary for the chock to be removed from the side frame so that the Wedge carried on the end of the spring 27 will be positioned against or closely adjacent the chock support 32.

Assuming the truck be disassembled and the side frame to be supported on wheel axles, the spring 27 and the wedge 15 may be inserted into the side frame opening 20 either through the bolster opening or through the window 21. The spring is placed on the seat 26a of the web 25 with the wedge seated on the top end of the spring. A pin is then inserted through the sideframe apertures 70 and 71 in front of the spring to hold the Wedge out of the bolster opening. The bolster is then inserted into the side frame and seated on springs 11 to attain a vertical and horizontal position relative to the side frame as shown in FIG. 6. Thereafter the pin is withdrawn from the apertures 70, 71 to allow the wedge 15 to settle into the lateral recess of the bolster against the wear plate 18. Y

The next and final element to be put into place is the chock 28. This is accomplished by inserting the pry bar 51 through the boss aperture 66 into contact with the seat 62 therefor at the small end of the wedge and prying upwardly on the pry bar to depress the wedge to an approximate position as shown in FIG. 3. The

chock 28 may then be inserted into position in front of the chock seats 35, 36 along the path indicated by FIG. 3. Pressure on the friction Wedge by the pry bar is then released to allow the wedge to move upwardly into wedging relation with the wear plate 16 in the bolster recess and the front chock surface. In disassembling the car truck of FIGS. 1 to 6, the operations just described are followed in reverse order.

In the event that replacement of theworn wedge or broken wedge spring is necessary, the chock is first removed through its opening 40 in the side wall 24. In the case of a broken spring, depressing the wedge 15 by the pry bar may not be necessary. However, re-

placement of a worn wedge will necessitate use of the pry bar to release the chock from its working position. Assuming the bolster 5 to be in working position within the side frame, and the chock to be removed, transfer of the wedge or the wedge spring to or from the opening 20 of the side frame will be effected through the window 21.

FIGS. 7 and 8 illustrate a car truck and chock, respectively, of modified design. The car truck of FIG. 7 is identical with that of FIG. 1 except for the reentrant and projecting relationship of the chock 28A and the chock support 32A of the side frame 6A. To indicate structure in FIGS. 7 and 8 analogous to, but modified with respect to, structure indicated by numerals in FIGS. 1 to 6, the letter A is added to the corresponding numeral from FIGS. 1 to 6. that the chock may be constructed with its rear side comprising areas 38A, 39A, arranged in a reentrant dihedral angle of which the apex extends in a transverse direction of the side frame. The areas 35A, 36A of the chock seat, on the other hand, project in a dihedral angle complementary to that of the chock. These differences of construction in no way change the procedure above set forth in respect to the first described embodiment.

The terms and expressions which have been employed herein are used as terms of description and not of limitation and there is no intention of excluding such equivalents of the invention described or of portions thereof as fall within the scope of the claims.

What is claimed is:

1. A railway car truck comprising:

(A) a bolster;

(B) a side frame having: 7

(1) transversely spaced side walls,

(2) a bolster opening in said side walls receiving said bolster with its length in transverse relation to the length of the side frame,

(3) a window in said sidewalls in longitudinally spaced relation with the bolster opening,

(4) a passageway contiguous with said bolster opening and extending away therefrom between said walls to the window, and

('5) a support fixed between said walls adjacent said passageway defining a chock seat spaced from said bolster opening and facing thereinto;

(C) a friction wedge disposed in the passageway with FIGS. 7 and 8 illustrate" in projecting and re-entrant relationship along a vertical plane parallel to said side walls to prevent shifting of the chock along said seat and, on the opposite from side, engaging the other divergent surface of the wedge;

(E) An abutment disposed between said walls in spaced relation with the support and in spaced facing relation with the wedge;

(F) resilient means reacting with the wedge and the abutment, the abutment being supported in a position fixed with respect .to the side frame to urge the wedge against said bolster side and the chock;

(G) one of said walls having another opening in approximate registry with the adjacent end of the chock V positioned against said seat, and of a size permitting passage of the chock into and out of the side frame;

(H) said wedge being movable out of engagement with the chock toward said abutment by compressing said resilient means to release the chock from engagement with said seat for passage of the chock from the support through said other opening; and

(I) said support being spaced across the passageway from other transversely extending portions of the side frame to enable passage of the wedge and the gesilient means through the passageway to said win- 2. The railway car truck of claim 1 wherein:

' (A) said surfaces of the wedge diverge from a smaller end portion defining a pry bar receiving seat toward its wider end, said wedge being recessed from its wider end toward the smaller end to define a spring seat disposed between said divergent surfaces;

(B) said wall of the side frame defines an open region adjacent said pry bar receiving seat; and

(C) one of said side frame walls has an aperture therethrough contiguous with said region defining a fulcrum point fora pry bar extending therethrough into contact with said pry bar receiving seat.

3. The car truck of claim 1 comprising:

(A) detent means for preventing movement of the chock through said side wall opening comprising means on said side frame overlapping means on said chock in the longitudinal direction of the side frame when said chock is seated on said chock seat;

(B) said overlapping means moving out of overlapping relationship at slight spacing of the chock with respect to said chock seat;

(C) said other opening located for passage of the chock therethrough at said spacing. I v

4. A railway car truck comprising:

(A) a bolster;

(B) a sideframe having:

(1) transversely spaced side walls,

(2) a bolster opening in said side Walls receiving said bolster with its length in transverse relation to the length of the side frame,

(3) a window in said side walls spaced from said opening in the longitudinal direction of the side frame,

(4) a passageway extending between said walls from the bolster opening to the window, and

(S) a support fixed between said walls adjacent said passageway defining a chock seat spaced from said bolster opening and facing thereinto;

(C) a friction wedge disposed in the passageway having two outer surfaces diverging from a smaller end portion toward its wider end;

(D) means disposed between said surfaces adjacent said smaller end defining a pry bar receiving seat and a spring seat recessed inwardly from the wider end toward the pry bar receiving seat;

(E) one of said surfaces engaging a side wall of the bolster;

(F) a chock positioned within the passageway with its opposite ends facing transversely of the side frame the chock engaging the other divergent surface of the wedge on a front side and, on the rear opposite side, engaging said chock seat with opposed engaging surfaces of the chock and the chock seat extending in projecting and reentrant relationship along a plane parallel to said side walls;

(G) said side frame having fixed therein a spring seat spaced transversely of the passageway in opposed spaced relation with the wedge spring seat; and

(H) a spring engaging, and standing between, said spring seats in a state of compression;

(I) one of the side walls "having another opening in approximate registry with an adjacent end of the chock in working position against said seat, said other opening being of a size and contour permitting passage of the chock into and out of the side frame;

(I) said wedge being movable out of engagement with the chock toward said spring seat by compressing said spring to release the chock from engagement with said chock seat for passage of the chock from the support through said other opening;

(K) said support being spaced across the passageway from other transversely extending portions of the side frame to enable passage of the wedge and the resilient means through the passageway to said window;

(L) said one side wall having a pry bar aperture extending therethrough into an open region immediately adjacent said pry bar seat;

(M) said one wall providing a fulcrum surface within said aperture for a pry bar extending therethrough into contact with said seat.

5. The car truck of claim 4 wherein:

(A) both the rear side of said chock and said chock seat are in projecting and reentrant relationship, respectively, and both comprise areas of which the planes meet in approximately equal dihedral angles extending transversely of the side frame.

6. The car truck of claim 4 wherein:

(A) the rear side of the chock and said chock seat are in reentrant and projecting relationship, respectively, and both comprise areas the planes of which meet in approximately equal dihedral angles; said dihedral angles extending transversely of the side frame.

7. The railway car truck of claim 4 wherein:

(A) the support is spaced from the bolster opening a distance equal to substantially the maximum dimension of the wedge in said direction to afford substantial vertical passage of the wedge between the bolster and the support with the chock removed.

8. The railway car truck of claim 4 wherein:

(A) the chock has spacer means projecting from the end of the chock facing the other of said side walls and into abutting relation with said other side wall.

9. The car truck of claim 4 wherein:

(A) the chock has a lug on a lateral surface extending between said front and rear sides; and

(B) said other opening is extended in the longitudinal direction of the side frame away from said seat to enable passage of the chock through said other opening along a path in spaced relationship with the chock seat; and

(C) said other opening has a notch receiving said lug when the chock occupies said path, and said lug moves out of registry with said notch upon engagement of the chock with the chock seat.

10. The car truck of claim 9 wherein:

(A) said areas of the chock seat and rear side of the chock are approximately symmetrical relative to the apex of the respective dihedral angles;

(B) said chock has spacer means projecting from each end for engaging the other of said side walls; and

(C) the other one of said side walls encloses a chockreceiving region opposite said other opening.

11. The car truck of claim 4 wherein:

(A) said side frame comprises a floor for said bolster opening,

(B) an upstanding lip defines the lower extremity of the bolster opening,

(C) a tension member extends along underneath the said floor wall and inclines upwardly toward the ends of the side frame, and

(D) a web inclines upwardly away from the lower extremity of said bolster opening in integral relation with side wall portions of the tension member, said web defining said spring seat of the side'frame.

12. The car truck of claim 4 wherein:

(A) a pair of columns spaced longitudinally of the side frame defines the lateral extremities of said bolster opening; 1

(B) said columns have opposed flanges projecting horizontally beyond said side Wall;

(C) said side walls and said flanges define bosses transversely coextensive with said flanges;

(D) said bosses project in horizontal transverse registry with a region adjacent the smaller end of said wedge;

(E) said boss has an opening in its laterally outward extremity for receiviny a pry bar.

13. The car truck of claim 4 wherein:

(A) each side wall has an aperture in horizontal transverse registry with the corresponding aperture of the other for receiving a pin in both apertures and in engagement with the side of the spring facing toward said bolster opening;

(B) said pin-receiving apertures are located relative to the bolster opening to support a pin extending therethrough disposing said wedge supported on said spring in free-length condition substantially against said support with the chock removed.

14. A side frame for a car truck of the type having 40 a friction bolster snubbing mechanism wherein the side frame supports a friction wedge against the bolster by means of a spring and a removable chock supported by the side frame against the wedge, the side frame having:

(A) transversely spaced side walls,

(B) longitudinally spaced columns defining a bolster opening in said side walls extending through the side frame in transverse relation with its length;

(C) a window defined in said side walls in longitudinally spaced relation to the bolster opening, and a passageway contiguous with the bolster opening and extending away therefrom between said walls to said window;

(D) a support fixed between said walls adjacent said passageway defining a seat for a wedge-engaging chock spaced from the bolster opening and facing thereinto; and

(B) an abutment fixed between said walls in spaced relation with the support and facing obliquely toward the bolster opening toward a friction wedge-receiving region immediately adjacent said seat defined by the support;

(F) said support being spaced across the passageway from other transversely extending portions of the side frame for passage through the passageway to the window of a wedge and a wedge spring used with the side frame;

(G) one of said walls having another opening contiguous with a region between the walls immediately adjacent said chock seat, said other opening providing passage for a chock between said chock seat and the exterior of the side frame.

15. The side frame of claim 14 wherein:

(A) said chock seat forms a dihedral angle.

16. The side frame of claim 14 in combination with a chock wherein:

(A) said side wall having said other opening has overlapping relation with the chock in position on said seat to prevent passage of the chock through said other opening.

References Cited by the Examiner UNITED STATES PATENTS Anderson 105-207 Anderson 105-207 Duryea 105-207 1 Cottrell 105-197 Oelkers 105-19 Davidson 105-207 X Shaw 105-197 Couch 105-197 Couch 105-197 Wullf 105-207 X Carlson et a1. 105-197 X Wulfi et a1. 105-207 X Tack et a1. 105-197 X ARTHUR L. LA POINT, Primary Examiner.

Examiners.

H. BELTRAN, Assistant Examiner. 

1. A RAILWAY CAR TRUCK COMPRISING: (A) A BOLSTER; (B) A SIDE FRAME HAVING: (1) TRANSVERSELY SPACED SIDE WALLS, (2) A BOLSTER OPENING IN SAID SIDE WALLS RECEIVNG SAID BOLSTER WITH ITS LENGTH IN TRANSVERST RELATION TO THE LENGTH OF THE SIDE FRAME, (3) A WINDOW IN SAID SIDEWALLS IN LONGITUDINALLY SPACED RELATION WITH THE BOLSTER OPENING, (4) A PASSAGEWAY CONTIGUOUS WITH SAID BOLSTER OPENING AND EXTENDING AWAY THEREFROM BETWEEN SAID WALLS TO THE WINDOW, AND (5) A SUPPORT FIXED BETWEEN SAID WALLS ADJACENT SAID PASSAGEWAY DEFINING A CHOCK SEAT SPACED FROM SAID BOLSTER OPENING AND FACING THEREINTO; (C) A FRICTION WEDGE DISPOSED IN THE PASSAGEWAY WITH ONE OF TWO DIVERGING SURFACES AGAINST A SIDE WALL OF THE BOLSTER; (D) A CHOCK POSITIONED WITHIN THE PASSAGEWAY WITH OPPOSITE ENDS FACING TRANSVERSELY OF THE SIDE FRAME, THE CHOCK HAVING A REAR SURFACE ENGAGING SAID CHOCK SEAT IN PROJECTING AND RE-ENTRANT RELATIONSHIP ALONG A VETICAL PLANE PARALLEL TO SAID SIDE WALLS TO PREVENT SHIFTING OF THE CHOCK ALONG SAID SEAT END, ON THE OPPOSITE FRONT SIDE, ENGAGING THE OTHER DIVERGENT SURFACE OF THE WEDGE; (E) AN ABUTMENT DISPOSED BETWEEN SAID WALLS IN SPACED RELATION WITH THE SUPPORT AND IN SPACED FACING RELATION WITH THE WEDGE; (F) RESILIENT MEANS REACTING WITH THE WEDGE AND THE ABUTMENT, THE ABUTMENT BEING SUPPORTED IN A POSITION FIXED WITH RESPECT TO THE SIDE FRAME TO URGE THE WEDGE AGAINST SAID BOLSTER SIDE AND THE CHOCK; (G) ONE OF SAID WALLS HAVING ANOTHER OPENING IN APPROXIMATE REGISTRY WITH THE ADJACENT END OF THE CHOCK POSITIONED AGAINST SAID SEAT, AND OF A SIZE PERMITTING PASSAGE OF THE CHOCK INTO THE AND OUT OF THE SIDE FRAME; (H) SAID WEDGE BEING MOVABLE OUT OF ENGAGEMENT WITH THE CHOCK TOWARD SAID ABUTMENT BY COMPRESSING SAID RESILIENT MEANS TO RELEASE THE CHOCK FROM ENGAGEMENT WITH SAID SEAT FOR PASSAGE OF THE CHOCK FROM THE SUPPORT THROUGH SAID OTHER OPENING; AND (I) SAID SUPPORT BEING SPACED ACROSS THE PASSAGEWAY FROM OTHER TRANSVERSELY EXTENDING PORTIONS OF THE SIDE FRAME TO ENABLE PASSAGE OF THE WEDGE AND THE RESILIENT MEANS THROUGH THE PASSAGEWAY TO SAID WINDOW. 